Question

resolva os sistemas de equações:3x+y=12 x-y=-16

Answer 1

3x+x=4x
4x=12
x=12/4
x=3
y=-16

Answer 2

x-y=-16
x=y-16

3x+y=12
3(y-16)+y=12
3y-48+y=12
3y+y=12+48
4y=60
y=60:4
y=15

x=y-16
x=15-16
x=-1